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Arlington, VA, United States

Larocque E.J.,Dewberry
Pipelines 2015: Recent Advances in Underground Pipeline Engineering and Construction - Proceedings of the Pipelines 2015 Conference | Year: 2015

Construction is ongoing of a 100-year service life 5.25-mile 42-and 48-inch welded steel pipeline, conveying raw river water from the Potomac River for a 40 MGD water supply system in an urbanizing county in northern Virginia. Ductile iron pipe (DIP) and welded steel pipe (WSP) were specified to create price competition. Transient modeling incorporated material-specific celerity values and showed that vacuum due to surge was more severe than positive surge. Air vacuum relief valves were located at each high point and 4 non-high points where transient surges were predicted. Cathodic protection was designed, consisting of a bonded coating and galvanic anodes. All bids received were for WSP. Lay schedule and shop drawings review assessed alignment, joint types and pulls. Constrained easements prompted reduced radii elbows. The heat shrink sleeve dissipates heat from joint welding after backfill. Daily lay production of 250 feet is planned. The strength of single lap welds was considered. Each weld is to be magnetic particle tested. © 2015 ASCE. Source

Mallin M.A.,University of North Carolina at Wilmington | McAuliffe J.A.,University of North Carolina at Wilmington | McIver M.R.,University of North Carolina at Wilmington | Mayes D.,Wilmington Storm water Services | Hanson M.A.,Dewberry
Journal of Environmental Quality | Year: 2012

Hewletts Creek, in Wilmington, North Carolina, drains a large suburban watershed and as such is affected by high fecal bacteria loads and periodic algal blooms from nutrient loading. During 2007,a 3.1-ha wetland was constructed to treat stormwater runofffrom a 238-ha watershed within the Hewletts Creek drainage. A rain event sampling program was performed in 2009-2010 to evaluate the efficancy of the wet land in reducing pollutant loads from the storm water runoffpassing through the wet land. During the eight storms sampled, the wet land greatly moderated the hydrograph and retained and/or removed 50 to 75% of the inflowing storm water volume. High removal rates of fecal coliform bacteria were achieved, with an average load reduction of 99% and overall concentration reduction of >90%. Particularly high (>90%) reductions of ammonium and orthophosphate loads also occurred, and lesser but still substantial reductions of total phosphorus (89%) and total suspended solids loads(88%) were achieved. Removal of nitrate was seasonally dependent, with lower removal occurring in cold weather and a high percentage (90%+) of nitrate load removal occurring in the growing season when water temperature exceeded 15°C. Long-term before-and-after sampling in downstream Hewletts Creek proper showed that, after wetland construction, statistically significant average decreases of 43% for nitrate, 72% for ammonium, and 59% for fecal coliform bacteria were realized. Wetland features contributing to the high pollutant control efficiancy included available space for a large wetland, construction of deep forebays, and a dense and diverse aquatic and shoreline plant assemblage. © American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. Source

Yannes C.D.,Dewberry | Lownes N.E.,University of Connecticut | Garrick N.W.,University of Connecticut | Johnston R.J.,Clark University
Transportation Research Record | Year: 2010

The ability to interpret and understand public perception of public transit and the built environment that it can create is imperative to the creation of a successful transit system. This research uses stated preference choice surveys in a hypothetical bond referendum to investigate public response to transit systems with particular service and placemaking attributes. The survey asks each participant to compare and choose one of two new transit service options or a "none of the above" option. The options are described by six attributes: service type, stop environment, travel time, fare, comfort, and the corresponding increase in taxes. Fitting a conditional logit model to these data allows the quantitative comparison of transit system configurations to ascertain the public's willingness to pay for the specific attributes. This study finds that people place a significant value on the quality of public spaces created by public transit, captured here through the use of digitally rendered built environments that capture several aspects of good public spaces: wide sidewalks, narrow streets, greenery, reduced building setbacks, multistory development, and human activity. Source

Ingargiola J.,FEMA Building Science Branch | Moline J.,Dewberry
Forensic Engineering 2012: Gateway to a Better Tomorrow - Proceedings of the 6th Congress on Forensic Engineering | Year: 2013

The National Flood Insurance Program (NFIP) requires that all new, belowbase flood elevation (BFE) construction in the regulatory floodplain be constructed with "materials resistant to flood damage." To provide a quantitative approach to evaluating resistance to flood damage, the Federal Emergency Management Agency (FEMA) Building Science Branch has developed a pre-standard on evaluating flood damage-resistant materials. The pre-standard outlines procedures for identifying the flood damage resistance rating of building construction materials based on mechanical and aesthetic characteristics. The primary users of the standard will be manufacturers who will subject their materials and assemblies to the testing requirements and local building officials who will use the ratings to determine what is allowed in below-BFE construction. In an effort to evaluate the structural and health impacts of contaminated floodwaters on building materials and assemblies, FEMA Building Science is also undertaking a laboratory research task. The task sets out to develop a standard contaminated floodwater for use in evaluation and to evaluate the physical and environmental impacts of that floodwater on building materials and assemblies. © ASCE 2013. Source

Said H.,Santa Clara University | Berger L.,Dewberry
Practice Periodical on Structural Design and Construction | Year: 2014

Because of the negative environmental and social impacts of built environment activities, several rating systems were developed in the last two decades to help professionals evaluate the sustainability of their design and construction decisions. A recent study revealed that industry leaders reported the shortcomings of these rating systems to provide accurate valuation of the return on their green investments. The study suggested the development of new evaluation processes that consider the triple-bottom-line (TBL) aspects (social, environmental, and financial) of project sustainability in a more holistic approach. Accordingly, this paper identifies the gaps between current practices and envisioned TBL-based practices through the following three main tasks: (1) surveying industry professionals to identify their current practices and required skills of sustainable design and construction; (2) surveying a sample of national academic engineering programs to identify current offerings of required sustainability courses; and (3) applying needs assessment to highlight the gaps and needed actions for achieving envisioned practices. It is proposed to implement a top-bottom action plan to develop new TBL-based processes that better inform sustainable/green investors and owners. © 2014 American Society of Civil Engineers. Source

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